Can anybody recommend good/clean/safe truck stops on m20 down from london to dover?
Cheers!
Good for food yes. Clean, passable . Safe 
Oakdene cafe off the M26 .
Just off of J10 M20 -
when heading coastbound take the 4th exit off of the roundabout (signed A2070). At the first roundabout you come, turn left into Waterbrook Avenue. Carry on along there, until you get to the barrier / gatehouse at the entrance.
Google map link: Google Maps
Details of prices: http://www.hgvtruckstops.co.uk/modules.php?name=News&file=article&sid=28
Dover truckstop, down A2, over traffic lights with Husk on the right, to the ■■■■■ with McDonalds on it, take 3rd exit and follow signs.
Or Ashford truckstop on M20.